Arduino 20 minute Script

[G+_Sean Miller]

Arduino 20 minute Script

I want to design an Arduino (maybe a Raspberry Pi, but I want it to be more robust and fast booting) that will run a script over 20 minutes.

At 1 minute activate these relays, at 2 minutes activate these other relays, etc.

The script would be activated by pressing a start button, so not based on time-of-day. I'd need the script to be pausable, resettable, etc.

 

My question is what is the best way to walk through a script over twenty minutes and still keep it interruptible and pausable. Would a RTC jerry rigged to not keep time-of-day work? How would I pause it?

Thank you very much for your time.

Sean

[G+_Jason Perry]

I have always wondered how to make a full system with the fastest boot time possible. An Arduino would be the fastest; but, I have thought about a light weight full system with a display for a while.

[G+_Matt Koglin]

Check out Arduino interrupts. They allow you to specify a pin or pins that, when changed, interrupt the main loop and perform a specific operation, after which looping continues.

 

playground.arduino.cc - Arduino Playground - Interrupts

 

There are likely some examples published code that does most of what you need! Good luck!

[G+_Sean Miller]

But I have a lot of interesting side ideas about hooking up an lcd display to display the time, etc. If I use an ESP8266, then I could link to it via webpage and edit the script, but that's a whole other ball of wax I'm not ready to dive into yet.

[G+_Jim Hofmann]

If I don't have a clear understanding of what's needed, I usually start with pseudo code. Then add real code.

 

define/init variables & constants

 

if a Button Pushed then

startTime = millis()

 

if millis() - startTime > 1000 then

relay1 = on

else

relay1 off

 

or maybe

 

relay1 = millis() - startTime > 1000

 

So this is where I'd start but the best thing is just jump in, the water's fine. :)

[G+_Sean Miller]

millis()...that sounds very promising. THank you very much.

[G+_Matt Koglin]

Start small and increase in difficulty as your frustration decreases :) If this is all new, you will certainly run into difficulties but know that Google is always there to help!

[G+_Ben Reese]

The Arduino's built in clock may be accurate enough for your needs. I haven't done too much testing, but in the little bit that I have done it seemed adequate.

 

I used an nRF24L01 chip to talk to a Pi and get the time, then used AES encryption to send the time back to the Pi. All just proof of concept stuff and I only let it run for a few days. But it worked!

 

I agree that using variables to store your times and letting the loop keep running is better than pausing for 20 minutes, or whatever. I used that method a few years ago for a refrigerator door alarm (tones at 30 and 45 seconds open then constant beep at 60).

[G+_Paul Hutchinson]

Ben Reese the built-in oscillator is almost certainly accurate enough for such short period time keeping. A resonator will typically be within 0.5% and a crystal within to 0.01%. It's only long run timing that needs a more accurate clock e.g. 0.0002% = 1 minute/year.

[G+_Sean Miller]

Thank you very much. I think millis() combined with interrupt functions should work okay. Now that I have an idea of what I'm doing, I'm off to the races.